Pros
It's a chance to meet other musicians with the same interest as you. You could use the product knowledge to land another job in the music industry or you could go sell cars and probably make more money. I worked with someone whose son was making more money delivering pizzas. Some think it's "cool" to work in a music store but the reality is that it's no different than any other job. It's hard for me to give best reasons to work at Guitar Center. It's worked for some people but it didn't work out for me at all. Good luck.
Cons
The pay versus the work. To work for commission only, with what Guitar Center pays, is a tough thing to do. Which is why they have such a high turn over rate. If you're a young, single guy or girl and you have roommates, you can probably make it work. But if you need a "real world" salary and have a family, it isn't a good move. Pretty much everything about working at Guitar Center is negative. I'm trying to meet the quote of this,so I'm going to keep typing until I make the quote they need, which will happen now.